A total of 120 postmenopausal women, of all races, aged between 43-58, with or without a history of breast cancer, and experiencing hot flashes or night sweats are currently being recruited for a research study. This study investigates the effects of soy protein on menopausal symptoms and hormone levels. Women are screened over the phone and if they meet the pre-screening criteria they are sent a packet of screening materials. Upon receipt of this packet the participant is called and if eligible they begin the intervention portion of the protocol. Participants are randomly assigned to consume soy or placebo bars for the duration of the intervention which is 12 weeks. During this period of intervention participants provide four blood samples (2 at the beginning and 2 at the end), two urine samples (1 at the beginning and 1 at the end of the 12 wks), hot flash logs, 3 day food records, and questionnaires throughout the 12 weeks.